Cisco Cisco IOS Software Release 12.3(11)T

In some rare instances, if you have installed the VIC2-2FXO or the VIC2-4FXO and configured the voice 
port for groundstart signaling, you may have difficulty connecting some outgoing calls. The problem 
relates to the FXO groundstart voice port failing to detect a tip-ground acknowledgment, resulting in an 
unsuccessful call setup. 

If you encounter this problem, upgrade your Cisco IOS software image to the latest version (for example, 
if you have Release 12.3(11)T installed, upgrade to Release 12.3(11)T2). This should fix the problem.

If this problem still occurs, you must enable the groundstart auto-tip command in the configuration of 
the FXO voice port. When you are placing outgoing calls, this ensures that the circuit detects a 
tip-ground acknowledgment from the far end and completes the connection within the time-out 
parameter. For information about the groundstart auto-tip command, refer to the 

For more information about this problem and more comprehensive troubleshooting steps, use the 
reference provided in the 

. You can search the website using 

keywords groundstart, analog, and fxo to obtain information on the topic described here.

This section provides a configuration example for the following:

This section provides an example of partial output from the show command after channel bank support 
has been configured:

Router# show startup-config

! 

voice-card 1 

! 

voice-card 2 

! 

voice-card 4 

! 

! 

controller T1 1/0 

framing esf 

linecode b8zs 

ds0-group 1 timeslots 1 type e&m-wink-start 

! 

controller T1 2/0 

framing esf 

linecode b8zs 

ds0-group 1 timeslots 1 type fxs-loop-start 

! 

controller T1 4/0 

framing esf 

linecode b8zs 

ds0-group 1 timeslots 1 type fxo-loop-start